What was found
(CAN) ENROUTE, THE LOAD MASTER OBSERVED AN UNUSUAL SOUND FROM THE CARGO BAY AREA. UPON INVESTIGATION AN UNUSUAL GAP WAS NOTICED BETWEEN THE LANDING GEAR BAY WEB AND THE BOTTOM EDGE OF THE DRAG ANGLE VERTICAL FLANGE. THE GAP WAS ESTIMATED AT .125 FROM STA 570 TO 580. THE CREW ELECTED TO RETURN WHERE THE ACFT LANDED WITHOUT INCIDENT. INVESTIGATION REVEALED THAT AN APPARENT FASTENER FAILURE COMMON TO THE STA 577 BEAM AND THE DRAG ANGLE GENERATED THE GAP. THE ACFT WAS REPOSITIONED UNDER PERMIT WHERE FURTHER ASSESSMENT IS ONGOING.